Just an opinion on my part that I've tamed down so as not to seem so politically incorrect, offensive and vehemently opposed to the idea... When they start being favorably compared to the rest of the dirt bikes featured in magazines, then is the time to consider one.
There are varying levels of reliability. The more you pay, the more you get. I believe that SSR and Piranha are the leading brands, anything other than that is "buyer beware." If you know what you are getting into they aren't a bad deal, but if you want to compare XR or TTR reliability, then you have to sustain a rigorous maintenance schedule. But I know that my SSR was pretty bullet proof, once I sorted out the little gremlins (which were likely PO issues and not manufacturer). Soft bolts and inconsistent torque values were the major issues that I experienced as the second owner, but I understand that if you clean, lube, and retorque all of the critical frame/chassis fasteners and change the engine oil up front that they are pretty reliable for play bikes. Once you start racing them then you better invest in a high quality brand.
I’ve read about bolts coming loose on several reviews. I want something to cruise the trails with my daughter. But on the other hand. I would also like something I could race on occasion at the Herrin Compound. I should probably just get an crf100 or 150 and be done with it. Buddy of mine has a crf 100 for sale I’m considering but at the price of an Apollo 125 brand new for $300 cheaper kind of makes it tough.
Completely different bikes and purposes between the 125 pit bikes and the CRF/XR. The XR sucks as a trail bike with an adult, but it's a great graduation bike for any kid. For flat track, I believe that the TTR125 and XR100 are the best bikes due to their relaxed layouts, and the pit bikes are better for MX and aggressive offroad riding. If you plan on hitting any bumps, the XR will beat you up, but the pit bikes usually have adjustable (and longer travel) suspension.
Here's my favorite XR100 flat track video: I'm wearing the camera and my buddy is on my other 100, and the only pit bike I have ever seen at this track was on the outside of the track with a thrown chain. All the rest of the mini bikes were XR100's or a couple of CRF150f's (not counting the little kids on their minis). If I were to get a pit bike for flat track, I would make sure it was a 17" front and 14" rear wheel version just to keep the wheelbase a bit longer and slow the front a bit. I would think that a 14" front on dirt would be sketchy, but a 16" front on asphalt is pretty stable.
